Subclinical hypothyroidism tied to heart risk.(Clinical Rounds)

WASHINGTON -- Elderly adults with subclinical hypothyroidism and a thyroid stimulating hormone level at or above 7 mIU/L are at increased risk for heart failure, Nicolas Rodondi, M.D., reported at a conference on cardiovascular disease epidemiology and prevention sponsored by the American Heart Association.

However, adults aged 70-79 with subclinical hypothyroidism with TSH values below 7 mIU/L are not at increased risk for heart failure (HF). Subclinical hypothyroidism does not appear to be associated with other cardiovascular events in that age group, said Dr. Rodondi of the University of California, San Francisco.

Previous studies have shown that subclinical hypothyroidism--in which [T.sub.4] is normal but TSH is elevated (4.5 mIU/L or above)--is associated with elevated total cholesterol, LDL cholesterol, and C-reactive protein. But data on cardiovascular outcomes are conflicting, he noted at the conference, also sponsored by the National Heart, Lung, and Blood Institute.

The current study included 2,740 men and women aged 70-79 participating in the Health, Aging, and Body Composition Study, funded by the National Institute on Aging. Subjects with abnormal [T.sub.4] levels or TSH levels at or below 0.1 mIU/L had been previously excluded.

The 339 subjects with subclinical hypothyroidism at baseline were less likely than the 2,401 euthyroid subjects to be black (25.4% vs. 41.8%), but did not differ significantly by age or gender. At baseline, total cholesterol was higher for those with subclinical hypothyroidism (211.5 vs. 204.5 mg/dL). About 30% of ...